|Location Map ( geo)|
|The Bridge in 2009|
|Metal Bridge, Cumberland|
| 1970 (west structure)|
2007 (east structure)
|Crossings related to the M6|
|Linstock Bridge • Lune Bridge • Mossband Viaduct • Samlesbury Bridge • Thelwall Viaduct|
Metal Bridge is where the M6 crosses the River Esk, two miles south-east of the Anglo-Scottish border at Gretna. (The Esk is the largest river in the area but the border follows the smaller river Sark.)
The first bridge on the site, which gave the location its name, was built by Thomas Telford in 1820 as part of his commission to improve the Carlisle-Glasgow road. Before Telford the most downstream crossing of the Esk was at Longtown on the present A7. This original bridge was similar to his bridge built at Bonar Bridge in the Highlands, itself a development of Craigellachie Bridge. It was this bridge, constructed of Iron, that gave the original name of Metal Bridge.
Since 2007 there have been two bridges side by side. The downstream bridge was built in 1970 as part of the dualling of the A74, and originally carried both two-lane carriageways. In 2008 when the A74 was upgraded to form the M6 (filling the so-called Cumberland Gap), this bridge was refurbished to carry both the northbound carriageway of the M6 and the new parallel minor road for non-motorway traffic. The upstream bridge was was built new in 2007 to carry the southbound M6.
The newer bridge has four spans, its piers being aligned with alternate piers of the 8-span older bridge. The deck of the older bridge is carried on numerous concrete beams, that of the newer bridge on five steel beams. The steelwork of the newer bridge was placed by launching in two stages from the north end, minimising works in the river.
400 yards downstream is the Esk railway viaduct which is the last crossing of the river before the Solway Firth.